Power device for delivering power to electronic devices

ABSTRACT

An energy efficient apparatus includes a switching device, a frequency dependent reactive device, and a control element is provided. The switching device is coupled to a source of electrical power and includes a pair of transistors and is adapted to receive a control signal and to produce an alternating current power signal. The frequency of the alternating current power signal is responsive to the control signal. The frequency dependent reactive device is electrically coupled to the pair of transistors for receiving the alternating current power signal and producing an output power signal. The frequency dependent reactive device is chosen to achieve a desired voltage of the output power signal relative to the frequency of the alternating current power signal. The control element senses an actual voltage of the direct current power signal and modifies the control signal delivered to achieve the desired voltage of the direct current power signal.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of prior U.S. patent application Ser.No. 13/588,262, filed Aug. 17, 2012, which was allowed on Jul. 7, 2015,the disclosure of which is hereby incorporated by reference in itsentirety.

FIELD OF THE INVENTION

The present invention relates generally to power device circuits, andmore particularly, to a power circuit which transforms electrical powerutilizing a frequency dependent reactive device.

BACKGROUND OF THE INVENTION

The Energy Crises Requires Demand Side Response That Lowers CurrentLoads. The Energy Crisis is upon us worldwide. For instance, the U. S.Department of Energy predicts that by 2015 there will not, on theaverage, be enough electric power to supply average demand in the U.S.

One of the controllable offenders is “Vampire Loads”. Also call “WallWort Power” or “Standby Power” this electricity waste makes up a largeportion of homes' or offices' miscellaneous electric load and is a largewaste of power. Vampire Load producers includes cell phone chargers, laptop chargers, notebook chargers, calculator chargers, small appliances,and other battery powered consumer devices.

The U.S. Department of Energy said in 2008:

“Many appliances continue to draw a small amount of power when they areswitched off. These “phantom” loads occur in most appliances that useelectricity, such as VCRs, televisions, stereos, computers, and kitchenappliances. This can be avoided by unplugging the appliance or using apower strip and using the switch on the power strip to cut all power tothe appliance.”

According to the U.S. Department of Energy, the following types ofdevices consume standby power:

-   -   1. Transformers for voltage conversion. (Including cell phone,        lap top and notepad, calculators and other battery powered        devices that use wall chargers).    -   2. Wall wart power supplies powering devices which are switched        off. (Including cell phone, lap top and notepad, calculator,        battery powered drills and tools, all of which have wall        chargers and have either completely charged the batteries or are        actually disconnected from the device).    -   3. Many devices with “instant-on” functions which respond        immediately to user action without warm-up delay.    -   4. Electronic and electrical devices in standby mode which can        be woken by a remote control, e.g. some air conditioners,        audio-visual equipment such as a television receiver.    -   5. Electronic and electrical device which can carry out some        functions even when switched off, e.g. with an electrically        powered timer. Most modern computers consume standby power,        allowing them to be woken remotely (by Wake on LAN, etc.) or at        a specified time. These functions are always enabled even if not        needed; power can be saved by disconnecting from mains        (sometimes by a switch on the back), but only if functionality        is not needed.    -   6. Uninterruptible power supplies (UPS)

All this means that even when a cell phone, lap top or like device iscompletely charged, current is still flowing, but not accomplishinganything and wasting electricity. Most recently manufactured devices andappliances continue to draw current all day, every day—and cost youmoney and add to the Energy Crisis Worldwide.

The National Institute of Standards and Technology (NIST) (a division ofthe U.S. Department of Commerce) through its Buildings TechnologyResearch and Development Subcommittee in 2010 stated its goals forreducing “plug loads,” stating:

“The impact of plug loads on overall consumption is quite significant.For commercial buildings, plug loads are estimated at 35% of totalenergy use, for residential 25%, and for schools 10%.

Opportunities for lowering plug loads include:

-   -   1) more efficient plugged devices and appliances,    -   2) automated switching devices that turn off unused appliances        and reduce “vampire” loads from transformers and other small but        always on appliances, or    -   3) modifying occupant behaviors.”

The present invention is aimed at one or more of the problems identifiedabove to provide better efficiencies.

SUMMARY OF THE INVENTION

In one aspect of the present invention, an apparatus comprises aswitching device and a frequency dependent reactive device. Theswitching device is coupled to a source of electrical (inrush) power andis adapted to receive a control signal and to produce an alternatingcurrent power signal. The frequency of the alternating current powersignal is responsive to the control signal. The frequency dependentreactive device is electrically coupled to the switching device forreceiving the alternating current power signal and producing an outputpower signal having a voltage level. The frequency dependent reactivedevice is chosen to achieve a desired voltage of the output power signalrelative to the frequency of the alternating current power signal.

In another aspect of the invention, an apparatus including a switchingdevice, a frequency dependent reactive device, and a control element isprovided. The switching device is coupled to a source of electricalpower and includes a first pair of transistors in a totem poleconfiguration. The switching device is adapted to receive a controlsignal and to produce an alternating current power signal. The frequencyof the alternating current power signal being responsive to the controlsignal. The frequency dependent reactive device is electrically coupledto the first pair of transistors for receiving the alternating currentpower signal and producing an output power signal having a voltagelevel. The frequency dependent reactive device is chosen to achieve adesired voltage of the output power signal relative to the frequency ofthe alternating current power signal. The control element is coupled tothe switching device and the frequency dependent reactive device forsensing an actual voltage of the direct current output power signal andresponsively modifying the control signal delivered to fine tune theswitching device to achieve the desired voltage of the direct currentoutput power signal.

In another aspect of the present invention, a power circuit forproviding electrical power at a desired voltage level from analternating current power source is provided. The power circuit includesa rectifying circuit, a switching device, a control element, and afrequency dependent reactive device. The rectifying circuit iselectrically coupled to the alternative current power source forproducing a rectified AC power signal. The switching device is coupledto the rectifying circuit and includes first and second pairs oftransistors. Each pair of transistors is arranged in a totem poleconfiguration fixed at 180 degrees of each other. The first and secondpairs of transistors drive a high-side output and a low-side output,respectively, to produce an alternating current power signal. Thefrequency of the alternating current power signal is responsive to acontrol signal. The control element is coupled to the switching devicefor delivering the control signal to the switching device. The frequencydependent reactive device is electrically coupled to the first andsecond pairs of transistors for receiving the alternating current powersignal and producing an output power signal. The frequency dependentreactive device includes first and second reactive elements and arectifier. The first and second reactive elements are electricallycoupled to the high-side and low-side outputs, respectively, and to therectifier, and are chosen to achieve the desired voltage of the outputpower signal relative to the frequency of the alternating current powersignal. The control element is configured to modify the control signaldelivered to the switching element to fine tune the switching device toachieve the desired voltage of the output power signal.

This invention works for both battery powered devices and direct powereddevices. With a communication chip included in the SmartProng™Technology Plug/cord, powered appliances can receive a command toshut-off the appliance/device at certain times (usually designated as“Demand Response” times by the Electrical Utility) and thus cover theentire plug load market with added energy efficiency.

Many similar existing electronic devices use a “Post-Regulation System”which extracts the exact power flow from a wall outlet then modifies itto an approximately desired AC voltage, usually through the use of atransformer, which is then converted to pulsating DC through the use ofa rectifying system (usually in a circuit board), commonly through theuse of a full wave bridge. Then an electrolytic capacitor is used toprovide an unregulated DC voltage. Finally, a linear regulator device isused to provide the desired regulated DC power. Because the regulator isat the end of this chain, this is described herein a as a“Post-Regulation System.” All of the parts in the chain provide losseswhich come in the form of heat and waste of electricity (loss). In thePost-Regulation Systems, the largest loss typically comes from thelinear regulator followed closely by the transformer.

This invention is a method for a design and utility patent for“Pre-Regulating” power current loads for devices which makestransformers obsolete, and regulating battery fulfillment, turning-offpower when the battery is full and saving wasted energy.

One way to replace the transformer in such a system is through capacitordrop technology which is described herein. This process hinges on acapacitor's ability to pass an AC voltage that diminishes withfrequency. For a given frequency, such as 60 cycle AC, it is possible toselect a value that will deliver a desired AC output for a given load.This characteristic is similar to a valve in a water pipe. Because ofthis mode of action, this process is almost lossless.

In the current invention, the capacitors are used on the circuit boardinstead of a transformer.

The present invention utilizes capacitor drop technology, by housing itin or connected directly to the plug prong or prongs, which are thenplugged into and AC outlet, makes the prongs themselves one or morecapacitors. One advantage is that the voltage leaving the outlet socketis limited right from the start. This conserves energy and makes theSmartProng Plug safer. Thus safety and efficiency are embodied in a newand unique way into the same product. The miniature capacitors which areeither embedded into one or more prongs or are connected to one or moreprongs and housed in the plug can have a fixed value, like a plug thatonly delivers 5 volts AC at 1 Amp which would be the 5 watts needed tocharge a cell phone. Or a fixed value could deliver 10 volts AC at 2Amps for the 12 watts needed to power an iPad or similar notebook.Alternatively, the capacitance can be housed on the circuit board,replacing the need for the transformer and linear regulator combination.

In this configuration just the fixed capacitance could be utilized, or achip, like Maxim's MAX8971 could be integrated with the SmartProngcircuitry to create intelligence that would sense when the battery isfull and disconnect the prong(s) capacitor from the AC outlet, thusshutting off the Vampire Load.

The current invention uses an embedded processor which controls theprocess. This processor could also contain or be coupled with a carriercurrent system (communication over power lines) or wirelesscommunication chip which would enable remote operation by the powereddevice or other remote system.

The invention modifies and controls the capacitance of a capacitor dropsystem, and eliminates the need for the transformer linear regulatorcombination at the end of the chain. Instead, it controls the amount ofcurrent (amp×volts) that exits by frequency modulation.

As such, the capacitor charging technology is a very efficient becausethe two most heat producing and wasteful portions of the chain, i.e. thetransformer and the linear regulators, are eliminated altogether.Moreover, many external charging devices provide less (700-800 mA) thanthe 1 A needed to adequately charge a phone, much less the 2.4 A neededto charge and run (while charging) devices like a tablet (i.e. a SamsungGalaxy or an iPad) or the 9.2 A needed to charge and/or run a notebookor laptop. The current invention can alter the voltage and amp outputsto be able to either charge one or more cell phones, or one or moretablets, or one or more notebooks/laptops, or alternatively one or morecell phones and one or more tablet, notebooks, and or laptops. Allcharging combinations of cell phones, tablets, notebooks, and/or laptopsare possible. The current invention's software and microprocessorrecognizes through its logic in the microprocessor the draw from thebattery as connected and analyzes the ramp up draw from that battery andthen either sends 1 A (for charging a cell phone) or up to 2.4 A fordevices like a tablet; or up to 9.2 A for charging a notebook or laptop,which the current invention can either do alternatively or at the sametime. In one embodiment, the acceptable input voltage can range from alow of 85V-a high of 300V worldwide. Output voltage is device dependentbut 5V to 19V are possible.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a block diagram of a power circuit for use, for example, in apower supply, according to an embodiment of the present invention;

FIG. 2 is a schematic of the power circuit of FIG. 1, according to anembodiment of the present invention;

FIG. 3 is an isometric drawing of a first view of a power circuit havinga housing, according to an embodiment of the present invention;

FIG. 4 is an isometric drawing of a second view of the housing of FIG.3;

FIG. 5 is an isometric drawing of an alternative power circuit housing;

FIG. 6 is an isometric drawing of a side view of the housing of FIG. 3;

FIG. 7 is an isometric drawing of a second side view of the housing ofFIG. 3;

FIG. 8 is an isometric drawing of an opposite side view of the housingof FIG. 3;

FIG. 9 is an isometric drawing of an opposite side view of thealternative power circuit housing;

FIG. 10 is another isometric drawing of the housing of FIG. 3;

FIG. 11 is a further isometric drawing of the housing of FIG. 3;

FIG. 12 is an isometric drawing of the alternative power circuithousing;

FIG. 13 is a cutaway drawing of the power circuit housing of FIG. 3;and,

FIG. 14 is a schematic of a LED circuit, according to an embodiment ofthe present invention;

FIG. 15 is a drawing of a dust shield associated with the housing ofFIG. 3, according to an embodiment of the present invention;

FIG. 16 is an illustration of a prong element for use with the dustshield of FIG. 15;

FIG. 17 is a first view of an alternative housing for use with the powercircuit, according to an embodiment of the present invention; and,

FIG. 18 is a second view of the alternative housing of FIG. 17; and

FIG. 19 is a flow diagram illustrating aperture of the power current ofFIG. 1, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF INVENTION

Referring to the Figures, wherein like numerals indicate like orcorresponding parts throughout the several views, a power device 2having a first power circuit 10 is provided. As shown in FIG. 1, thefirst power circuit 10 includes a switching device 12, a frequencydependent reactive device 14 and an output section 16.

The first power circuit 10 may be used to convert the power provided bya source of electrical power of a first type to electrical power of amore desirable type. For example, the first power circuit 10 may be usedto convert electrical power received from a source of electrical power18, such as a power grid. The source of electrical power 18 may beprovided as an alternating current at a given voltage, e.g., 120 voltsat a frequency of 60 Hertz (the North American Standard) or 220-240volts at a frequency of 50 Hz (the European Standard) to a moredesirable voltage. The acceptable input voltage range for the inventionis a low of 85 volts to a high of 300 volts at either 50 or 60 Hertz soas to accept a world-wide range of mains power. The output electricalpower, at the desired voltage, may be supplied at a direct current, suchas 5 volts direct current (VDC) or an AC signal of any desirablewaveform.

In one aspect, the first power circuit 10 of the present inventionprovides a power supply circuit which replaces the transformer of priorart power supplies with the in-line frequency dependent reactive device14. As discussed more fully below, the frequency dependent reactivedevice 14, in general, passes an alternating current whose voltage levelchanges with frequency. In other words the frequency dependent reactivedevice 14 passes current at varying efficiency which is dependent onfrequency. By proper value selection the capacitor can allow a losslessvoltage drop. Therefore, the power circuit 10 avoids the inefficienciesof the standard power supply circuit which includes a transformer. Theinefficiencies of the prior art transformer based circuits are typicallyexhibited, at least in part, as excess generated heat.

Returning to FIG. 1, the switching device 12 is coupled to the source ofelectrical power 18. The switching device 12 is adapted to receive acontrol signal and to produce an alternating current power signal. Thefrequency of the alternating current power signal is responsive to thecontrol signal.

As explained more fully below, the control signal is generated by acontrol element 20 (which may be microprocessor based). In oneembodiment, the control signal is a variable frequency. The frequency ofthe control signal is modified to deliver the desired output power.

The frequency dependent reactive device 14 is electrically coupled tothe switching device 12 and receives the alternating current powersignal and produces an alternating current output power signal having areduced voltage level. The frequency dependent reactive device is chosento achieve a desired voltage of the output power signal relative to thealternating current power delivered by switching device 12.

Returning to FIG. 1, the first power circuit 10 may provide electricalpower from the output section 16 through an appropriate power connectoror port 22, such as a universal serial bus (USB) port. In theillustrated embodiment, the power device 2 includes a second powercircuit 24, which is electrically coupled to the control element 20, andprovides output power through a second power connector or port 26. Inone embodiment, the second power circuit 24 is similar or identical tothe first power circuit 10.

A first embodiment of the first power circuit 10 is shown in FIG. 2. Thefirst power circuit 10 includes an input or rectifying circuit 28. Theinput circuit 28 is electrically coupled to the source of electricalpower 18. The input circuit 28 converts the input electrical power to aDC voltage at a voltage dependent upon the input power. For example, inone embodiment the input power is 120 volts at 60 Hz, and the inputcircuit 28 converts the input power to approximately 180 volts (DC).

In the illustrated embodiment, the input circuit 28 includes a firstfull-wave bridge rectifier 30 having first and second input terminalscoupled to the high and low sides of the source of electrical power 18.The output terminals of the first full-wave bridge rectifier 30 arecoupled to a circuit which includes an inductor 32. The ends of theinductor 32 are electrically coupled to ground through first and secondcapacitors 36, 38, respectively. The full-wave rectified output of thefull-wave bridge rectifier 30 is converted into a DC voltage signal at,e.g., approximately 180 volts by this circuit.

The switching device 12 receives a control signal from the controlelement 20 and converts the DC voltage output of the input circuit 28into an alternating current power signal. The frequency of thealternating current power signal is responsive to the control signal.

In one embodiment, the switching device includes a first pair oftransistors 40A and a second pair of transistors 40B, both pairs 40A,40B are arranged in a totem pole arrangement.

In the illustrated embodiment, the first pair of transistors 40Aincludes a first P-channel MOSFET transistor 42 and a first N-channelMOSFET transistor 44. The second pair of transistors 40B includes asecond P-channel MOSFET transistor 46 and a second N-channel MOSFETtransistor 48.

Each pair of transistors 40A, 40B is driven by first and second drivercircuits 50A, 50B. The driver circuits 50A, 50B are electrically coupledto the control element 20. The driver circuits 50A, 50B receive thecontrol signal and deliver a driver signal to the respective pair oftransistors, 40A, 40B.

The first pair of transistors 40A drive the highside 52 of the output ofthe switching circuit 12 and the second pair of transistors 40B drivethe lowside 54 of the output of the switching circuit 12. The output ofthe first and second pairs of transistors 40A, 40B are 180 degrees outof phase with respect to each other. In other words, when the highside52 of the output of the switching circuit is high, the lowside 54 of theoutput of the switching circuit is low. And when the highside 52 of theoutput switching circuit is low, the lowside 54 of the output of theswitching circuit 12 is high.

In the illustrated embodiment, the first driver circuit 50A includes athird N-channel MOSFET transistor 56 coupled to the control element 20,a third P-channel MOSFET transistor 58 coupled to the third N-channelMOSFET transistor 56 and a resistor 60 coupled between the thirdP-channel MOSFET transistor 58 and ground. The first driver circuit 50Aalso includes a fourth N-channel MOSFET transistor 62 coupled betweenthe control element 20 and the first P-channel MOSFET transistor 42.

In the illustrated embodiment, the second driver circuit 50B includes afifth N-channel MOSFET transistor 64 coupled to the control element 20,a fourth P-channel MOSFET transistor 66 coupled to the fifth N-channelMOSFET transistor 64 and a resistor 68 coupled between the fourthP-channel MOSFET transistor 66 and a positive rail voltage, e.g., +15volts. The second driver circuit 50B also includes a sixth N-channelMOSFET transistor 68 coupled between the control element 20 and thesecond P-channel MOSFET transistor 46.

In the illustrated embodiment, each pair of transistors 40A, 40B consistof a P-channel MOSFET 42, 46 in a highside configuration over aN-channel MOSFET 44, 48 in a totem pole configuration. In thisembodiment, the square wave outputs of the driver circuits 50A, 50B arein phase, but offset as to the DC level.

In an alternative embodiment, the first and second driver circuits 50A,50B (and isolators 88, 90) may be replaced by integrated circuit (IC)drivers. Additionally, each pair of transistors 40A, 40B may be replacedby a pair of N-channel transistors in a totem pole configuration. Inthis arrangement, the square wave outputs of the IC drivers are 180degrees out of phase.

The frequency dependent reactive device 14 includes at least one pair ofreactive element like 70A, 70B in the illustrated embodiment. Since boththe highside 52 and the lowside 54 are driven, the frequency dependentreactive device 14 includes first and second reactive elements 70A, 70B.In the illustrated embodiment, the first and second reactive elements70A, 70B are capacitors 72A, 72B. The capacitors 72A, 72B may benano-capacitors, and may be based upon ferroelectric and core-shellmaterials as well as those based on nanowires, nanopillars, nanotubes,and nanoporous materials.

In practice, the frequency of the control signal from the controlelement 20 controls the frequency of the alternating current powersignal. For example, generally the switching circuit 14 creates analternating current having a peak voltage based on the output voltage ofthe input circuit 28 and having a frequency based on the control signal.Since the value of the capacitors 72A, 72B are chosen based on thefrequency of the alternating current power signal, the amount of powerutilized from the source of electrical power 18, and thus, theefficiency of the power circuit 10, 24 can be controlled.

In one embodiment, the output power signal is a DC voltage at a targetvoltage, e.g., 5 volts. As shown in FIG. 2, the frequency dependentreactive device 14 may also include a second full-wave rectifier 74 totransform the alternating current signal from the capacitors 72A, 72Binto a DC voltage.

The output subsection 16 of the power circuit 10 includes filters, andconditions the output of the switching circuit 14. The output section 16includes an inductor 76 and a capacitor 80.

The output section 16 also includes a voltage divider, comprised ofresistors 82, 84. The output of the voltage divider is fed to thecontrol element 20 (see below).

In the illustrated embodiment, the control element 20 includes amicroprocessor 86 and a lowside isolator 88 and a highside isolator 90.

The two highside isolator outputs are 180 degrees out of phase with eachother. The two lowside isolator outputs are also 180 degrees out ofphase with each other. The isolators 88, 90 disassociate the devicesbeing charged from the source of electrical power 18. The purpose ofthis isolation is to eliminate shock hazards to the user.

Using the voltage divider circuit 82, 84, the control element 20, i.e.,the microprocessor 86 can sense the actual voltage delivered (which canvary based on, e.g., manufacturing tolerances in the circuitcomponents). The voltage output of the voltage divider circuit 82, 84 isinput to an A/D input of the microprocessor 86. The control element 20can also sense the current being delivered through sense resistor 78.Based on the sensed voltage and current delivered, the control element20 can modify the frequency of the control signal to fine tune and moreaccurately control the output of the power circuit 10,.

In one aspect of the present invention, the microprocessor 86 or controlelement 20 monitors the output power signal (through the voltage dividercircuit 82, 84) and adjusts the control signals to the switching device12 and the frequency dependent reactive device 14 to keep the poweroutput within specification. The control element 20 includes themicroprocessor 86 and an associated control program. The output of thevoltage divider circuit 82, 84 is used to calculate/modify the frequencyof the output signal(s), i.e., the frequency is increased if morevoltage is required and lower if less voltage is required.

The control program may compensate for different output load conditions,component tolerances, component parameter variations at differentoperating points, and component changes due to temperature. The controlprogram also monitors several operating parameters to turn the switchingdevice off, which removes power from the output, if a condition that isunsafe or out of the operating range is detected.

In general, the control loop monitors the output power signal andadjusts the frequency of the switching device to make the output powersignal stay within its operating limits. The control loop uses thenominal characteristics of the frequency dependent reactive element 14for control decisions. For example, if the output power signal is belowthe operating limit, the frequency is changed to deliver more power tothe output. The control loop performs other tasks like: a slow startupsequence to keep from overpowering an attached load, and faultmonitoring and handling.

In one aspect of the present invention, the impedance of capacitors 72A,72B can be represented as ideal capacitors defined as:

${Z = \frac{1}{2\pi\;{fC}}},$

Where f represents the frequency of the control signal in Hertz and C isthe value of the capacitor in Farads. Since the value of the impedanceis inversely proportional to the frequency used, a capacitor value isselected that will produce the lowest required impedance at the highestdesirable signal frequency. In the present invention, the lowestpossible impedance is desired with the lowest possible input voltage(V_(i)), highest current load (I_(max)), and maximum acceptableswitching frequency (f_(max)).

The purpose of the capacitors 72A, 72B are to supply the secondary withan attenuated voltage source with which the secondary side will furtherregulate to the desired output. The signal applied to the capacitor, Vi,minus the desired voltage on the secondary side V_(s) is equal to thevoltage attenuation of the capacitors 72A, 72B. The current through eachcapacitor 72A, 72B is equal to the current demanded by the load on thesecondary. The desired Z of the capacitor is found using the followingequation:

$Z = {\frac{\left( {V_{i} - V_{s}} \right)}{I_{\max}}.}$

The proper value of the capacitor can be calculated using the idealcapacitor equation using Z and f_(max).

The capacitor value gives the total attenuation capacitance needed. Iffull isolation is required, then two capacitors are used to isolate bothsides of the AC signal. These two capacitors will be in a seriesconnection, and capacitors in series add in this relationship:

$C = \left( {\frac{1}{C_{a}} + {\frac{1}{C_{b}}\mspace{14mu}\ldots\mspace{14mu}\frac{1}{C_{n}}}} \right)^{- 1}$

For balancing of the circuit the two constituent capacitors C_(c) are ofequal value. Therefore,

${C = {\left( {\frac{1}{C_{c}} + \frac{1}{C_{c}}}\; \right)^{- 1} = \frac{C_{2}}{2}}},{and}$C_(c) = 2 * C.

The value of C_(c) is the value of the actual components placed in thecircuit.

With reference to FIGS. 4-16, in one embodiment of the presentinvention, the power device 2 is contained within a housing 100. In theillustrated embodiment, the housing 100 is comprised of a pair of halfshells (first and second half-shells 100A, 100B) which form a cavity inwhich the power device 2 is located. The pair of half shells 100A, 100Bmay be held together by clips, an adhesive, or fasteners, any suitablefastening means, and the like, or combinations thereof. In theillustrated embodiment, the power device 2 includes two power circuits10, 24 which provide power to the first and second ports 22, 26 whichare shown as USB ports which are located on the first and secondhalf-shells 100A, 100B, respectively. It should be noted that while inthe illustrated embodiment, two USB ports are shown, it should berecognized that either more or less ports may be provided, and may beeither based on a USB standard or other standards and connectors, likethat used in notebooks and laptops.

The housing 100 has a first end 102A and a second end 102B. Each end102A, 102B may controllably form an electrical plug 104A, 104B. Theelectrical plugs 104A, 104B may conform to different internationalstandards. For example, in FIG. 10, the first electrical plug 104A is aNorth American standard plug formed by the first end 102A and a firstpair of prongs 106A and the second electrical plug 104B is a Europeanstandard plug formed by the second end 102B and a second pair of prongs106B. With respect to FIG. 12, either plug may be configured to meet anyother standard such as the Australian standard (formed by thealternative end 104B′ and the alternative prongs 106C).

In practice, the device 2 has three modes: a storage mode, a first mode,and a second mode. In the storage mode, both sets of prongs 106A, 106B,106C are contained within the housing 100 (as shown in FIG. 3-9).

In the first mode, the prongs 106A comprising the first electrical plug104A are extended through a first set of apertures 108A in the first end102A (see FIG. 10)

In the second mode, the prongs 106B, 106C comprising the secondelectrical plug 104B, 104B′ are extended though a second set ofapertures 108B, 108B′ in the second end 102B, 102B′ (see FIGS. 11 and12).

With respect to FIGS. 3-9, 13, and 15, the power device 2 includesactuation device 110. The actuation device 110 includes a button 112, aprong receiving apparatus 114, and a dust cover 116. The prong receivingapparatus 114 includes first and second slots which receive first andsecond double ended prong structures 118, 120. Each double ended prongstructure 118, 120 forms one of the pairs of each set of prongs, asshown. The prong structures 118, 120 are electrically coupled to thefirst and second power circuits 10, 24.

The button 112 is affixed or formed on an opposite side of the dustcover 116. The button 112 extends through, and is movable along, a slot122 formed in the housing 100. Actuation of the button 112 in eitherdirection along the slot 122 extends one of the pairs of prongs 106A,106B, 106C through the respective apertures 108A, 108B, 108B′.

As shown in FIG. 13, the dust cover 114 wraps around the inner surfaceof the housing 100. The lower portions 124 of the dust cover 114 coversor blocks the apertures to prevent or minimize entry of dust and othercontaminants into the housing 100. As the button 112 is manipulatedtowards one end of the slot 122, the respective prongs 106A, 106B, 106Care moved towards and extend through the apertures 108A, 108B, 108C. Atthe same time, the dust cover 110 is also moved. A respective upperportion 126 of the dust cover 110 is moved towards the respectiveapertures 108A, 108B, 108C such that a respective set of apertures 128,130 in the dust cover are generally aligned with the apertures, therebyallowing the prongs 106A, 106C, 106C to pass therethrough.

With reference to FIG. 14, in one embodiment the power circuits 10, 24includes three separate LED circuits 132A, 132B, 132C (each comprising aresistor in series with a LED, as shown). The first and second LEDcircuits 132A, 132B are used to illuminate the first and second USBports 22, 26, respectively. The third LED circuit 132C is located behinda logo 134 located on each side of the housing 100.

Lighting of the logos 134 using the third LED circuit 132C, in oneembodiment, is used to power is being applied to the device being poweror charged through one of the ports. Lighting of the ports may be usedto confirm that the attached device (not shown) is being charged. Apulsing scheme may be implemented in order to communicate the currentrelevant state of charge. For example, the LED (for the respective USBport) may be rapidly pulsed when the device being charged is in a lowstate of charge with the pulse rate diminishing as the device approachesfull charge.

With reference to FIGS. 17 and 18, an alternative embodiment of thehousing 100′ is shown. The alternative housing 100′ includes first andsecond USB ports 22, 26 (located on opposite sides thereof) and a logo134. Separate pairs of prongs 106A, 106B are rotatably coupled to thehousing 100′ and electrically coupled to the power device 2.

INDUSTRIAL APPLICABILITY

In one aspect of the present invention, the power circuits 10, 24 areaimed at delivering a specified power output signal to an externaldevice connected, e.g., through the USB port 22, 26. Most externaldevices do not require a pure direct current (DC) signal to operatecorrectly. Many external devices will work with a power signal that hasa combination of alternating current (AC) and DC. The importantconsideration with a power output signal that has a combination of ACand DC is to not let the peak value exceed some limit. This limit istypically the value of a pure DC power output signal which isaccomplished with this invention. For example: a USB device typicallyneeds a 5V DC power signal. The limit is 5V so the peak value of thecomposite AC/DC signal cannot exceed 5V. To keep the power output signalfrom exceeding the limit, the control element will sense the peak valueof the output power signal rather than the DC, or average, component. Ifthere is no AC component, the peak value of the output power signal inthe invention is equal to the DC component.

The power device 2 will supply a desired fixed voltage. For a givendevice, the desired voltage may be different. For example, for a cellphone, the desired voltage is typically 5 volts. The frequency of theoutput signals (from the microprocessor) is adjusted to always supplythe target voltage. If a load requires more current, the frequency willincrease so that the fixed output voltage stays in an acceptable range.For different device requiring different voltages, the power device 2will output consecutively larger voltages and monitor the current. Whena threshold current is being drawn from the power device 2, themicroprocessor makes a threshold determination as to what voltage theoutput should be controlled, e.g., 5 volts, 9 volts, 12 volts or up to19.6 volts for devices like notebooks and/or laptops.

In another aspect of the present invention, a battery and/or chargingcapacitor (supercap 98) may be used as a power storage device to powerthe microprocessor 86. Also, current as regulated from the feedback loopmay be delivered to the microprocessor, avoiding the need for an initialpower supply for the microprocessor. It is desirable to keep themicroprocessor on through either a electricity source supply or chargedby the supercap 98 and/or battery at all times such that the applicationof loads, i.e., devices, may be detected and their state of charge tobegin a charging cycle. During normal charging operation, power isdiverted from one of the charging outputs to provide power to charge thesupercap 98 and/or battery. In the case when the power device 2 iseither first utilized or has been inactive for a period of time, abootstrap power supply may be temporarily activated to supply theinitial power. Once the supercap 98 and/or battery has been charged, thebootstrap power supply may be turned off.

In another aspect of the present invention, the power device 2eliminates vampire loads. The microprocessor 86 and feedback loopcontinually monitor the draw of current from the charging device. Fromthe initiation of the charging cycle, a table is formed in themicroprocessor 86 which analyzes the current draw. During the chargingcycle the microprocessor 86 continues to monitor the current draw thatis being consumed by the charging device through the current sensorresistor 78. The microprocessor 86 then analyzes that draw and reportswhen the draw begins to wane due to a fully charged device. Themicroprocessor 86 also stands on alert to sense when the currentdiminishes as the charging device approaches a full charge. From theinitial outrush of current to the charging device through the entirecharging cycle, the microprocessor 86 uses algorithms to determine whena charging device is fully or nearly fully charged (and when the currentdraw approaches zero). Then, the power device 2 shuts off power from itsinrush supply and shuts down the charging and power draw from the inrushsource. Also, the power device 2 can detect when a device is connectedby sensing the current draw. At any time when there is no current draw,the power device shuts off, avoiding the ongoing electrical waste thatnormally exist when a charging device is still plugged into a walloutlet, but no phone is attached.

In the illustrated embodiment, the first power block or input circuit 28is connected to the mains, i.e., the sourced electrical power 18, whichconsist of either 120 volts at a frequency of 60 Hertz (the NorthAmerican Standard) or 220-240 volts at a frequency of 50 Hz (theEuropean Standard). This power is supplied to a full wave bridge 30which rectifies the AC into pulsating DC. This pulsating DC is convertedinto a continuous DC voltage through the use of the capacitors 36 and 38and the inductor 32. The DC voltage supplied is approximately 180V DC inthe case of the North American Standard or approximately 360V DC in thecase of the European Standard.

The charging delivery system starts with the microprocessor 86 whichdelivers high frequency square waves via four ports. These signals arefed through isolator devices 88 and 90 to their respective FET driversub assemblies 50A, 50B. In the case of sub assembly 50A a signal fromthe highside isolator 90 is supplied to an FET 62 via its gate. Thepurpose of the FET 62 is to increase the voltage swing of the squarewave from logic levels (3.3V peak to peak) to a voltage level of about15V peak to peak required to drive the power FET 42 the first drivercircuit 50A also contains lowside driver FETs these FETs are suppliedfrom the lowside isolator 88 which is injected into the first isolator'sgate 56. This signal is amplified and inverted and then fed in to asubsequent FET 58. This signal is also amplified and then inverted tocreate a 15V peak to peak signal suitable for driving respective powerFET 44.

The two power FETs 42, 44 are set up as a “Totem Pole” configuration.The top of the “Totem Pole” 42 is fed with the DC voltage supplied fromthe input circuit 28. The bottom FET 44 has its source attached toground. This arrangement allows for the “Totem Pole” junction 52 todeliver the square waves supplied by circuit 50A with a peak to peakvalue of 180V in the case of the North American Standard or a peak topeak value of 360V in the case of the European Standard.

Circuits 50B, 40B function identically to circuits 50A, 40A as describedabove with the exception that the delivered square wave at 54 is 180degrees out of phase with the square wave at 52.

These two square waves are fed into the frequency dependent reactivedevice which contains a full wave bridge that is supplied by signal 52via capacitor 70A. The bottom side of the bridge is fed signal 54 viathe capacitor 70B. Capacitors 70A and 70B are sized (capacitance value)to reduce the AC voltage output from the large peak to peak input (180Vto 360V peak to peak) to a more manageable voltage in the neighborhoodof 10 VAC. The rectified output of bridge 74 is fed into the outputcircuit 16. This output circuit consists of conductor 76 and capacitor80 which converts the pulsating DC from bridge 74 into an unregulated DCvoltage.

The balance of circuit 16 consists of a voltage sense assemblyconsisting of resistors 82 and 84 and a current sense resistor 78. Thevoltage sense assembly delivers a representation of the output voltage(that voltage which is delivered to the charging device) to one of themicroprocessor's A/D convertors. The sense resistor 78 delivers avoltage that is a representation of the current that is being consumedby the charging device. This signal is supplied to another A/D convertorwithin the microprocessor. These signals enable the microprocessor toadjust the output voltage to a precise 5 VDC regardless of the currentrequirements of the charging device.

With reference to FIG. 19, a boot time method 200 is shown. At boottime, the system initializes a charging routine at block 202. Themicroprocessor 86 then checks the current sense at block 204 to see if aload exists (block 206). If it does not, the microprocessor 88 turns offthe charging routine (block 208) and enters a sleep period (block 210).After the sleep period the method 200 returns to the charging routine(block 202). The method 200 will stay in this loop as long as no loadexists.

In the event that a load does exist (block 206) the method 200 checksthe voltage sets (block 212). The system then compares what it readswith the acceptable in band voltage (block 214). If the voltage is notout of band the routine goes to sleep (block 210). If the voltage is outof band (block 214), the routine then checks if it is too high or toolow (block 220).

If the voltage is too high the system decrements the output frequency(block 218) and then checks if the output frequency is at the lowestallowable setting (block 216). If yes, the routine goes to sleep (block210). If no, the microprocessor once again checks the voltage sense(block 212). The microprocessor 86 will continue this loop until theoutput voltage has been reduced to the desired amount or it reaches thelowest allowable setting.

If the voltage is too low, the microprocessor 86 increments the outputfrequency (block 222) and then checks if the output frequency is at thehighest allowable setting (block 224). If yes, the routine goes to sleep(block 210). If no, the method 200 once again checks the voltage sense(block 212). The method 200 will continue this loop until the outputvoltage has been increased to the desired amount or it reaches thehighest allowable setting.

Many modifications and variations of the present invention are possiblein light of the above teachings. The invention may be practicedotherwise than as specifically described within the scope of theappended claims.

What is claimed is:
 1. An apparatus, comprising: a voltage reductioncircuit electrically coupled to an electrical power source for receivingan input power signal from the electrical power source and delivering anoutput power signal to an electrical device the voltage reductioncircuit including: a switching device coupled to the electrical powersource, the switching device being adapted to receive a control signaland to produce an alternating current (AC) power signal, a frequency ofthe AC power signal being responsive to the control signal, theswitching device including a first pair of transistors and a second pairof transistors; a frequency dependent reactive device electricallycoupled to the switching device for receiving the AC power signal andproducing an output power signal having a voltage level that is lessthan a voltage level of the AC power signal, the frequency dependentreactive device including a first capacitor coupled to the first pair oftransistors and a second capacitor coupled to the second pair oftransistors, the first capacitor and the second capacitor beingconfigured to adjust the AC power signal for producing the output powersignal; and an electrical current sensor electrically coupled to thevoltage reduction circuit for sensing an electrical current being drawnby the electrical device from the voltage reduction circuit; and acontroller coupled to the electrical current sensor and the voltagereduction circuit, the controller configured to: receive, from theelectrical current sensor, a current signal indicative of current beingdrawn by the electrical device; detect an initial current draw from theelectrical device as a function of the received current signal andresponsively initiate a charging cycle; monitor a level of current beingdrawn by the electrical device during the charging cycle; and detect ifthe monitored level of current being drawn by the electrical device isless than a threshold level of current and responsively generate andtransmit the control signal to the first and second pairs of transistorsto operate the voltage reduction circuit to disconnect power to theelectrical device.
 2. An apparatus in accordance with claim 1, whereinthe first pair of transistors are configured to drive a highside of theAC power signal to the first capacitor and the second pair oftransistors are configured to drive a lowside of the AC power signal tothe second capacitor.
 3. An apparatus in accordance with claim 1,wherein the output power signal is a direct current (DC) power signal,the voltage reduction circuit includes a rectifier circuit coupled tothe first and the second capacitors for transforming the AC power signalinto the DC power signal.
 4. An apparatus in accordance with claim 1,the controller configured to: determine an initial level of currentbeing drawn by the electrical device upon detecting the initial currentdraw; and determine the threshold level of current as a function of theinitial level of current.
 5. An apparatus in accordance with claim 1,further comprising: a voltage sensor for monitoring a voltage level ofpower being delivered to the electrical device and transmitting themonitored voltage level to the controller, the controller configured togenerate and transmit the control signal to the voltage reductioncircuit to adjust the voltage level of power being delivered to theelectrical device.
 6. An apparatus in accordance with claim 5, thecontroller configured to adjust a duty cycle of the control signal beingtransmitted to the voltage reduction circuit to adjust the voltage levelof power being delivered to the electrical device.
 7. An apparatus inaccordance with claim 6, the controller configured to adjust the dutycycle of the control signal to maintain the monitored voltage levelwithin a predefined voltage range.
 8. An apparatus in accordance withclaim 5, the controller configured to adjust a level of current beingdelivered to the electrical device as a function of the monitoredvoltage level.
 9. An apparatus in accordance with claim 5, wherein theswitching device is configured to produce the AC power signal having afrequency being responsive to the control signal and the frequencydependent reactive device configured to transmit the output power signalhaving a voltage level determined as a function of the frequency of theinput power signal.
 10. An apparatus in accordance with claim 1, thecontroller configured to initiate a sleep mode if the initial currentdraw of the electrical device is not detected, initiate a predefinedsleep period, and initiate a start-up routine upon expiration of thepredefined sleep period including detecting the initial current draw ofthe electrical device upon detecting the input power signal.
 11. Anelectrical circuit for providing electrical power for use in chargingelectrical devices, comprising: a rectifier circuit configured toreceive an input AC power signal from an electrical power source andgenerate a rectified DC power signal; a switching device coupled to therectifier circuit and configured to receive the rectified DC powersignal and produce an intermediate AC power signal, the switching deviceincluding a first pair of transistors and a second pair of transistors;a frequency dependent reactive device coupled to the switching devicefor receiving the intermediate AC power signal and producing an outputDC power signal having a voltage level that is less than a voltage levelof the input AC power signal, the frequency dependent reactive deviceincluding a first capacitor coupled to the first pair of transistors anda second capacitor coupled to the second pair of transistors, the firstcapacitor and the second capacitor being configured to adjust theintermediate AC power signal for producing the output DC power signal;and an electrical current sensor electrically coupled to the frequencydependent reactive device for sensing an electrical current being drawnby the electrical device from the frequency dependent reactive device;and a controller coupled to the electrical current sensor and theswitching device, the controller configured to: receive, from theelectrical current sensor, a current signal indicative of current beingdrawn by the electrical device; detect an initial current draw from theelectrical device as a function of the received current signal andresponsively initiate a charging cycle; monitor a level of current beingdrawn by the electrical device during the charging cycle; and, detect ifthe monitored level of current being drawn by the electrical device isless than a threshold level of current and responsively generate andtransmit a control signal to the first and second pairs of transistorsto operate the switching device to disconnect power to the electricaldevice.
 12. An electrical circuit in accordance with claim 11, whereinthe first pair of transistors are configured to drive a highside of anAC power signal to the first capacitor and the second pair oftransistors are configured to drive a lowside of the AC power signal tothe second capacitor.
 13. An electrical circuit in accordance with claim11, including an output rectifier circuit coupled to the first and thesecond capacitors for transforming the intermediate AC power signal intothe output DC power signal.
 14. An electrical circuit in accordance withclaim 11, the controller configured to: determine an initial level ofcurrent being drawn by the electrical device upon detecting the initialcurrent draw; and determine the threshold level of current as a functionof the initial level of current.
 15. An electrical circuit in accordancewith claim 11, further comprising: a voltage sensor for monitoring avoltage level of power being delivered to the electrical device andtransmitting the monitored voltage level to the controller, thecontroller programmed to generate and transmit the control signal to theswitching device to adjust the voltage level of power being delivered tothe electrical device.
 16. An electrical circuit in accordance withclaim 15, the controller configured to adjust a duty cycle of thecontrol signal being transmitted to the switching device to adjust thevoltage level of power being delivered to the electrical device.
 17. Anelectrical circuit in accordance with claim 16, the controllerconfigured to adjust the duty cycle of the control signal to maintainthe monitored voltage level within a predefined voltage range.
 18. Anelectrical circuit in accordance with claim 15, the controllerconfigured to adjust a level of current being delivered to theelectrical device as a function of the monitored voltage level.
 19. Anelectrical circuit in accordance with claim 11, the controllerconfigured to initiate a sleep mode if the initial current draw of theelectrical device is not detected, initiate a predefined sleep period,and initiate a start-up routine upon expiration of the predefined sleepperiod including detecting the initial current draw of the electricaldevice upon detecting the input AC power signal.
 20. A method ofproviding electrical power for use in charging electrical devices with apower circuit, the power circuit being electrically coupled to anelectrical power source for receiving input power from the electricalpower source and delivering output power to an electrical device, thepower circuit including a current sensor, a controller, a switchingdevice and a frequency dependent reactive device, the switching devicebeing coupled to the electrical power source and including a first pairof transistors and a second pair of transistors, the frequency dependentreactive device being coupled to the switching device and including afirst capacitor coupled to the first pair of transistors and a secondcapacitor coupled to the second pair of transistors the first capacitorand the second capacitor being configured to adjust and AC power signalfor producing an output power signal, the method including thecontroller performing the steps of: receiving a current signalindicative of current being drawn by the electrical device from thecurrent sensor; detecting an initial current draw from the electricaldevice as a function of the received current signal and responsivelyinitiating a charging cycle; monitoring a level of current being drawnby the electrical device during the charging cycle; and, detecting ifthe monitored level of current being drawn by the electrical device isless than a threshold level of current and responsively generating andtransmit a control signal to the first and second pairs of transistorsto operate the power circuit to disconnect power to the electricaldevice.